300-R010-45G Datasheet, PDF (5/36 Pages) Magnetrol International, Inc. – Echotel® Model 300/301 Ultrasonic Non-Contact Transmitter For Level/Volume/Open Channel Flow

TRANSDUCER MOUNTING
CAUTION: Please read the entire installation section carefully prior to starting installation. Also read the Measurement
Range Calculations section on pages 3-4 to make sure that you have selected the proper level system for your application.
CAUTION: If equipment is used in a manner not specified by manufacturer, protection provided by equipment may be impaired.
GENERAL GUIDELINES
The unit can be provided as an integral mount Model 300
with the transducer connected to the transmitter housing, or
as a remote mount Model 301 with the transmitter mounted
as far as 500' (152 m) away from the transducer. Both the
transducer and the transmitter are approved for Class I,
Division 1, Groups B, C, & D areas.
TRANSDUCER MOUNTING LOCATION
Proper mounting of the ultrasonic transducer is very critical
to the operation of any non-contact ultrasonic application.
Both the accuracy and the reliability of the Model 300/301
can be adversely affected if the transducer is mounted
improperly. This section must be followed carefully to make
sure that the optimum mounting location is chosen, and that
proper mounting techniques are used for the transducer.
Several factors should be considered when selecting the
transducer location:
• Inherent dead band of the transducer
• Standpipes
• Application difficulties (foam, turbulence, vapors)
• Ultrasonic beam angle
TRANSDUCER DEAD BAND
The transducer must be mounted directly over the liquid sur-
face, as shown in Figure 1. Non-contact ultrasonic instru-
ments require a “dead band” or “blind space” between the
face of the transducer and the maximum liquid level. The
minimum dead band for the Model 300/301 is 18" (457 mm).
This dead band should be taken into consideration when
mounting the transducer. If the level must be measured all
the way to the top of the tank, the transducer should be
mounted in a standpipe as shown in Figures 2 and 3.
STANDPIPES
In applications where the material level may come into the
dead band, the transducer must be mounted in a standpipe.
The diameter of the standpipe should be at least 8" (203
mm); and its length should be limited to 11" (279 mm) from
transducer face. Refer to Figure 2.
Stand
pipe
2" NPT
Maximum 11"
(279 mm) or less
Transducer
8" (203)
Minimum I.D.
This end welded
or flanged
Figure 2
Transducer Mounting in Standpipe
Figure 3
Transducer Mounting for Tanks with Exhaust
Model 300
Flange
Air
Dead band
18" minimum
(457 mm)
Liquid
Maximum span
28.5' (8.7 m)
APPLICATION DIFFICULTIES
Typically the liquid surface is most turbulent at the fill point.
Foam on the other hand, is most likely to accumulate at the
opposite end of the fill. Since foam and turbulence can both
create difficulties in reflecting a strong ultrasonic signal back
into the transducer, it is best to pick a mounting location
away from these areas in the vessel.
Avoid installing the transducer in tank top openings that
exhaust heated air or vapors. The boundaries between the
vapors and the outside air often represent acoustic imped-
ance gradients that can cause troublesome sound reflec-
tions. In those installations, the transducer should be mount-
ed well away from the opening inside the tank, or in a stand-
pipe as illustrated in Figures 2 and 3.
Figure 1
Typical Transducer Mounting
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